How did this happen???

Capolini

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The ONLY thing I can think of is my OPUS BT-C3100 was way off. It is usually very consistent.

Batteries 4 X VTC6-BOD=6.22.2016-Received on 6.26.2017[Banggood special!] $2.50/each
After complaining they were old stock!:D

Here are the numbers when I tested them on 6.26.2017

Slot 1=3001mAh,Slot #2=3050mAh,Slot #3=3034mAh, Slot #4=2977mAh 4 Slot Median = 3015mAh

Today-1.19.2018

Slot #1=2750mAh, Slot #2=2818mAh,Slot #3=2717mAh, Slot #4=2792mAh 4 slot Median =2769mAh

Median Loss= 236mAh


HERE is where it does not make sense!

The MAX run time tests w/ my TK61vn V4 are basically identical in TIME and voltages, yet supposedly the batteries lost and average of 236mAh!


6.26.17 run time test****1.18.2018 test

15m=4.04v**************15m=4.00v
25m=3.91v**************25m=3.88v
35m=3.81v**************35m=3.79v
40m=3.76v**************40m=3.74v
50m=3.64v**************50m=3.62v

Any explanations besides error on Mr. Opus? Time is yours,,,,,,,,,,,,,,






 

Gauss163

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How many cycles? What voltage were they stored at? What was IR then and now?
 

WalkIntoTheLight

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Yeah, if they've been kept at full charge most of the time, then an 8% loss over the last 6 months is about what is expected.

The run time can be a bit misleading, unless you're sure the light is fully regulated and outputs are identical. Those voltages are not the same. You certainly wouldn't notice an 8% drop in average output.

I'd trust your OPUS more than a run-time test.
 

Capolini

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How many cycles? What voltage were they stored at? What was IR then and now?

60 CYCLES,,They are NOT stored, used at least twice a week with a full charge like ALL my batteries/lights in the rotation..............have no idea about the IR.

Why would the run times and voltages be basically the same when the mah has dropped by 200mAh plus,,,makes no sense in my mind.
 

Capolini

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Yeah, if they've been kept at full charge most of the time, then an 8% loss over the last 6 months is about what is expected.

The run time can be a bit misleading, unless you're sure the light is fully regulated and outputs are identical. Those voltages are not the same. You certainly wouldn't notice an 8% drop in average output.

I'd trust your OPUS more than a run-time test.

The run time test is really all that matters to me. Voltages are not exactly the same, however, 0.02v makes very, very little difference in run times.
 

Capolini

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You guys reminded me of something. and touched upon it. Maybe the run times are VERY similar but the output dropped ever so slightly because of slight capacity loss.

On the other hand I have had batteries[older] where the run time at max output noticeably decreased and the voltage difference was much more significant than 0.02v.
 

Gauss163

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60 CYCLES,,They are NOT stored, used at least twice a week with a full charge like ALL my batteries/lights in the rotation..............have no idea about the IR.

Why would the run times and voltages be basically the same when the mah has dropped by 200mAh plus,,,makes no sense in my mind.

By "storage voltage" I mean the voltage you keep them at when they are not being used. There can be a big difference in degradation if they have spent most of their lifetime (near) fully-charged vs. less extreme voltages.

Also, any significant increase in IR could cause changes, since it will affect the SOC where the OPUS terminates discharge, and may also impact your light tests in various ways. It's always a good idea to track IR since it is a major indicator of health.
 

WalkIntoTheLight

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60 CYCLES,,They are NOT stored, used at least twice a week with a full charge like ALL my batteries/lights in the rotation..............have no idea about the IR.

You didn't answer the question directly, but it does sound like you keep your batteries with a full charge most of the time. In that case, your 8% loss in capacity is normal.

You can extend the life of your batteries by not charging them up to 4.2v. You could, for example, only charge them up to 4.0v. That will be about an 80% charge, and it will greatly extend the life of your cells since you won't be keeping them at full charge all the time. But, obviously, the downside is your run time won't be as long.

If you can easily buy batteries, I wouldn't worry about it. It's only costing pennies per charge, even if you have to throw the battery out in a couple of years.
 

Capolini

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You didn't answer the question directly, but it does sound like you keep your batteries with a full charge most of the time. In that case, your 8% loss in capacity is normal.

You can extend the life of your batteries by not charging them up to 4.2v. You could, for example, only charge them up to 4.0v. That will be about an 80% charge, and it will greatly extend the life of your cells since you won't be keeping them at full charge all the time. But, obviously, the downside is your run time won't be as long.

If you can easily buy batteries, I wouldn't worry about it. It's only costing pennies per charge, even if you have to throw the battery out in a couple of years.

I was just curious and I do NOT worry about it because batteries are cheap and Liionwholsale is 1.5 miles away!

I would much rather have FULL charges and FULL power than worry about cell degradation.

In almost 6 years, treating the cells the same way, which is a full charge and staying that way for 3 days or so until they get used, the majority have performed well at least 3 years, some 4 and a few 5 years!
 
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night.hoodie

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Why would the run times and voltages be basically the same when the mah has dropped by 200mAh plus,,,makes no sense in my mind.


The run time test is really all that matters to me. Voltages are not exactly the same, however, 0.02v makes very, very little difference in run times.


How much runtime can you get with 200mAh? It's a tiny amount of capacity. That's like 1/3rd the capacity of the worst AAA NiMH cell evar, so at higher current, it might only be a minute or two. I think the reason your runtime is basically the same is because the capacity is basically the same. 200mAh is nothing, man, not even long enough to pee in the dark at 1A. I think you just posted so you could brag about Liionwholesaler being a couple dozen blocks from you.
 

WalkIntoTheLight

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I was just curious and I do NOT worry about it because batteries are cheap and Liionwholsale is 1.5 miles away!

I would much rather have FULL charges and FULL power than worry about cell degradation.

In that case, your cells are behaving perfectly fine according to your use, and you can buy new ones every couple of years for best performance.
 

Boris74

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Hey Cap, any temperature variation when the light was used?

This right here. I was going to say it yesterday but didn't have time. The current ambient temp will have more to do with it than everything else combined. If you use your lights in extremes of temps like I do it'll teach you that real quick.
 

Capolini

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Hey Cap, any temperature variation when the light was used?

I checked my records.I did not put as much detail in this post as usual.

Tail stand/no fan/Incremental w/ 5 minutes rest.

Loft temperature was 72F on the 6.27.2017 test. On the 1.18.2018 test loft temperature was 62F...........10 degrees cooler!

If anything the 1.18.2018 test would have slightly better results if air temp. was a factor
 
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